1. Field of the Invention
This invention relates to a corrosion resistant lead alloy for grids and plates used in lead-acid batteries.
2. Description of the Prior Art
Various combinations of materials have been proposed as additives to the lead alloys used in the grids and plates of lead-acid batteries.
The prior art lead alloys as exemplified in U.S. Pat. Nos. 5,298,350 and 5,434,025 describe the use of calcium as an additive for lead alloys, but limit its amount to a maximum of 0.06% by weight.
The lower the level of calcium the longer it takes for the alloy to become stiff enough for the manufacturing process.
Other prior art patents call for the use of calcium in a percentage weight range of 0.06 to 0.1%, with tin in the percentage weight range of 0.1 to 0.8% for maintenance free batteries.
There has also been interest in using low antimony lead based alloys, which contain antimony of about 1 to 2.5%, and the use of calcium-aluminum as additives in lead alloys.
Experiments were conducted using calcium as an additive in lead alloys in the weight range of 0.06 to 0.08, tin in the weight range of 0.3 to 0.6, silver in the weight range of 0.01 to 0.05, and copper in the weight range of 0.01 to 0.05 which alloys attain the required strength for the manufacturing processes quickly, and improve the life of the battery over the prior art alloys.